For the systematic study of the bryozoans in Cheju-do, the present study was done with the materials collected from 13 localities of Cheju-do during the period from 1965 to 1985. As a result, 52 species were reported, bringing total number of species known from Cheju-do to 74. Of them eleven species were new to Korean fauna. They were as follows: Tubulipora pulchra, Ellisina canui, Labioporella sinuosa, Mucropetraliella mucroaviculata, Emballotheca pacifica, Hippomenella spatulata, Microporella cribrosa, Smittina raigii, Smittoidea prolifica, Parasmittina triangularis and Escharoides excavata.